libstdc++-v3/testsuite/20_util/enable_shared_from_this/members/weak_from_this.cc

   1 // Copyright (C) 2015-2019 Free Software Foundation, Inc.
   2 //
   3 // This file is part of the GNU ISO C++ Library.  This library is free
   4 // software; you can redistribute it and/or modify it under the
   5 // terms of the GNU General Public License as published by the
   6 // Free Software Foundation; either version 3, or (at your option)
   7 // any later version.
   8
   9 // This library is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13
  14 // You should have received a copy of the GNU General Public License along
  15 // with this library; see the file COPYING3.  If not see
  16 // <http://www.gnu.org/licenses/>.
  17
  18 // { dg-options "-std=gnu++17" }
  19
  20 #include <memory>
  21 #include <testsuite_hooks.h>
  22
  23 #if __cpp_lib_enable_shared_from_this < 201603
  24 # error "__cpp_lib_enable_shared_from_this < 201603"
  25 #endif
  26
  27 struct X : public std::enable_shared_from_this<X> { };
  28
  29 static_assert( noexcept(std::declval<X&>().weak_from_this()) );
  30 static_assert( noexcept(std::declval<const X&>().weak_from_this()) );
  31
  32 void
  33 test01()
  34 {
  35   std::shared_ptr<X> sp(new X);
  36   auto wp1 = sp->weak_from_this();
  37   std::weak_ptr<X> wp2 = sp;
  38
  39   std::owner_less<> less;
  40   VERIFY( !less(wp1, wp2) && !less(wp2, wp1) );
  41   VERIFY( !less(wp1, wp2) && !less(wp2, wp1) );
  42 }
  43
  44 int
  45 main()
  46 {
  47   test01();
  48 }